ALT-801 (Altor BioScience)

MOMENTUM Phase 2 Obesity Trial (Week 24 Interim Analysis of 160 Subjects) Mean weight loss of 10.7% (placebo-adjusted 9.7%) at 2.4 mg dose at Week 24 Mean weight loss of 11.9% (placebo-adjusted 11.1%) in subjects weighing 115 kg or less at baseline at 2.4 mg dose at Week 24 Approximately 50% of subjects achieved 10% or more weight loss and approximately 20% of subjects achieved 15% or more weight loss at the 1.8 mg and 2.4 mg doses at Week 24 Robust reductions in waist circumference, serum lipids and blood pressure without meaningful increases in heart rate Rates of gastrointestinal (GI) adverse events (AEs) similar to earlier pemvidutide trials Phase 1b Type 2 Diabetes Safety Trial (Week 12 End-of-Study Analysis) 7.7% (placebo-adjusted 8.5%) weight loss at 2.4 mg dose at Week 12 Glycemic homeostasis maintained, with no significant changes in fasting glucose or HbA1c, and no hyperglycemia AEs Excellent tolerability with low rates of gastrointestinal AEs Altimmune to host conference call today at 8:30 am ET GAITHERSBURG, Md., March 21, 2023 (GLOBE NEWSWIRE) -- Altimmune, Inc. (Nasdaq: ALT), a clinical-stage biopharmaceutical company (the “Company”), today announced topline results from a Week 24 interim analysis of 160 subjects in its 48-week MOMENTUM Phase 2 obesity trial of pemvidutide along with the results of the 12-week Phase 1b safety trial of pemvidutide in subjects with obesity or overweight and type 2 diabetes. MOMENTUM Phase 2 Obesity Trial – Week 24 Interim Analysis The MOMENTUM Phase 2 obesity trial is being conducted at 30 sites across the U.S., with Dr. Louis Aronne, Professor of Metabolic Research and Professor of Clinical Medicine, Weill Cornell Medicine, a leading authority in obesity and obesity clinical trials, serving as the Principal Investigator. The trial was designed to enroll approximately 320 subjects with obesity or overweight with at least one co-morbidity and without diabetes. Subjects were randomized 1:1:1:1 to 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo administered weekly for 48 weeks in conjunction with diet and exercise. A pre-specified interim analysis was conducted after 160 subjects completed 24 weeks of treatment. Subjects in the interim analysis had a demographic composition similar to the full study population previously announced, with a median age of approximately 48 years, a median body mass index of approximately 36 kg/m2, and a median body weight of approximately 100 kg. Approximately 75% of subjects were female, and approximately 20% of subjects were of Hispanic ethnicity. At Week 24, subjects receiving pemvidutide achieved mean weight losses of 7.3%, 9.4% and 10.7% at the 1.2 mg, 1.8 mg, and 2.4 mg doses, respectively, with the placebo group experiencing a mean weight loss of 1.0% (p < 0.001 at all three doses vs placebo, efficacy estimand using a mixed model of repeated measures [MMRM] analysis). An impact of baseline body weight was observed, where subjects with baseline body weight less than or equal to 115 kg (75% of the study population) achieved mean weight losses of 8.2%, 10.6%, 11.9% and 0.8% at the 1.2 mg, 1.8 mg, 2.4 mg and placebo groups, respectively (p < 0.001 at all three doses vs placebo). Approximately 50% of subjects achieved 10% or more weight loss and approximately 20% of subjects achieved 15% or more weight loss at Week 24 at the 1.8 mg and 2.4 mg doses. Robust reductions in waist circumference (a measure of visceral fat) and serum lipids were also observed, and clinically meaningful reductions in blood pressure were achieved without meaningful increases in heart rate. Glucose homeostasis was also maintained, with no significant changes in fasting glucose or HbA1c. Regarding safety, upper GI events of nausea and vomiting comprised the majority of AEs. These events were predominantly mild and moderate in severity, dose-related and similar in frequency to those observed in prior trials of pemvidutide. Rates of lower GI AEs including diarrhea and constipation were notably low. This AE pro observed in the absence of dose titration at the 1.2 mg and 1.8 mg doses and with a limited 4-week dose titration at the 2.4 mg dose. One subject (2.4%) experienced a serious adverse event of nausea and vomiting requiring rehydration at the 2.4 mg dose. Treatment discontinuation rates were 28.2% in subjects receiving placebo and 24.0% in subjects receiving pemvidutide. The majority of placebo discontinuations were due to withdrawal of consent, while approximately half of the withdrawals across the pemvidutide dose groups were attributed to GI AEs. These discontinuations occurred almost entirely in the first 16 weeks of treatment. The protocol did not allow for dose reduction due to intolerability as employed in other incretin trials. “The weight loss achieved was impressive and bodes well for the effects that could be achieved at the completion of 48 weeks of therapy,” said Louis Aronne, M.D., Sanford I. Weill Professor of Metabolic Research and Professor of Clinical Medicine, Weill Cornell Medicine, and a paid scientific advisory board member for Altimmune, Inc. “I believe that the reductions in total and LDL cholesterol, blood pressure and waist circumference have the potential to be compelling product attributes, if approved, for patients with risk factors for cardiovascular disease. The impact of baseline weight, which was likewise observed with semaglutide above 115 kg, suggests that higher doses could be an effective strategy in the population with more severe degrees of obesity.” “We regard these results as extremely promising,” said Vipin K. Garg, Ph.D., President and Chief Executive Officer of Altimmune. “The ability to achieve robust reductions in body weight, waist circumference, blood pressure, and serum lipids, together with the previously demonstrated best-in-class effects on liver fat reduction, suggest that pemvidutide has the potential to be an important treatment option for patients with obesity, especially those who are at risk for liver disease, dyslipidemia and related conditions.” Dr. Garg added, “We believe that the 1.2 mg and 1.8 mg doses used without dose titration would be attractive options for primary care physicians and that we have the opportunity to improve further upon the pro pemvidutide by utilizing higher doses in patients with more severe degrees of obesity, by allowing dose reduction and by employing a more prolonged titration for doses higher than 1.8 mg in our future trials. We look forward to completing our 48-week MOMENTUM obesity trial in the fourth quarter of 2023 and initiating a Phase 2 biopsy NASH trial in mid-2023.” MOMENTUM Week 24 Interim Analysis—Summary of Efficacy Findings Primary Endpoint: Body weight Placebo (n=39) 1.2 mg (n=40) 1.8 mg (n=40) 2.4 mg (n=41) ∆ Body weight, all subjects %, LSM (SE)1 -1.0 (0.8) -7.3 (0.8)*** -9.4 (0.8)*** -10.7 (0.9)*** Impact of Baseline Body Weight on Efficacy Placebo (n=28) 1.2 mg (n=30) 1.8 mg (n=31) 2.4 mg (n=31) ∆ Body weight, subjects with baseline weight ≤ 115 kg %, LSM (SE)1 -0.8 (1.0) -8.2 (1.1)*** -10.6 (1.1)*** -11.9 (1.1)*** Responder Analyses Placebo (n=28) 1.2 mg (n=33) 1.8 mg (n=33) 2.4 mg (n=26) % Subjects w/ ≥5% weight loss % 25.0% 66.7%** 66.7%*** 84.6%**** % Subjects w/ ≥10% weight loss % 0.0% 30.3%** 48.5%**** 50.0%**** % Subjects w/ ≥15% weight loss % 0.0% 6.1% 18.2%* 23.1%* Secondary Endpoints Placebo (n=39) 1.2 mg (n=40) 1.8 mg (n=40) 2.4 mg (n=41) ∆ Waist circumference cm, LSM (SE)1 -4.0 (1.5) -8.2 (1.5)** -8.8 (1.5)*** -10.2 (1.6)*** ∆ Total cholesterol mg/dl. mean (SE)2 -2.5 (4.7) -13.0 (4.7)** -14.5 (4.9)*** -16.5 (5.1)*** ∆ LDL cholesterol -1.1 (7.9) -5.5 (7.9) -10.3 (8.3) -12.7 (8.5) ∆ Triglycerides -3.3 (9.4) -25.1 (9.6)** -14.4 (9.9) -25.0 (10.3)** ∆ Systolic BP mm Hg, LSM (SE)1 -0.5 (2.6) -2.9 (2.5) -3.1 (2.7) -5.5 (2.8) ∆ Diastolic BP 0.5 (1.6) -0.1 (1.5) -1.4 (1.6) -1.8 (1.7) ∆ Heart rate bpm, LSM (SE)1 -2.4 (1.9) 0.0 (1.8) 1.0 (1.9) 0.6 (2.0) 1 MMRM, 2ANCOVA, *p < .05; ** p < 0.05, *** p < 0.001, ****p < 0.0001 compared with placebo MOMENTUM Week 24 Interim Analysis—Summary of Safety Findings Placebo (n=39) 1.2 mg (n=40) 1.8 mg (n=40) 2.4 mg (n=41) Adverse events (AEs) Serious AEs n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (2.4%)1 Discontinuations due to AE n (%) 1 (2.6%) 3 (7.5%) 4 (10.0%) 11 (26.8%) Gastrointestinal AEs Nausea AEs Mild, n (%) 2 (5.1%) 5 (12.5%) 9 (22.5%) 12 (29.3%) Moderate, n (%) 0 (0.0%) 3 (7.5%) 13 (32.5%) 9 (22.0%) Severe, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (2.4%) Vomiting AEs Mild, n (%) 0 (0.0%) 0 (0.0%) 2 (5.0%) 5 (12.2%) Moderate, n (%) 0 (0.0%) 2 (5.0%) 3 (7.5%) 4 (9.8%) Severe, n (%) 0 (0.0%) 0 (0.0%) 1 (2.5%) 1 (2.4%) Diarrhea AEs Mild, n (%) 0 (0.0%) 3 (7.5%) 2 (5.0%) 4 (9.8%) Moderate, n (%) 2 (5.1%) 0 (0.0%) 0 (0.0%) 2 (4.9%) Constipation AEs Mild, n (%) 0 (0.0%) 3 (7.5%) 1 (2.5%) 5 (12.2%) Moderate, n (%) 2 (5.1%) 2 (5.0%) 1 (2.5%) 1 (2.4%) Glycemic Control Fasting glucose Baseline, mg/dL mean (SD) 96.1 (9.8) 97.0 (12.2) 103.1 (12.1) 100.3 (12.9) Week 24, mg/dL mean (SD) 97.7 (11.4) 96.0 (11.2) 103.9 (14.4) 102.5 (18.4) HbA1c Baseline, % mean (SD) 5.5 (0.4) 5.6 (0.3) 5.5 (0.4) 5.5 (0.4) Week 24, % mean (SD) 5.5 (0.3) 5.5 (0.3) 5.6 (0.5) 5.6 (0.5) 1 Rehydration for nausea and vomiting Phase 1b Type 2 Diabetes Safety Trial The Phase 1b trial, which was conducted to evaluate the safety pro pemvidutide in subjects with overweight or obesity and type 2 diabetes, was comprised of 54 subjects randomized 1:1:1:1 to 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo administered weekly for 12 weeks. No caloric restrictions or lifestyle interventions were employed. Subjects were required to be 18-65 years of age with BMI ≥ 28 kg/m2 and type 2 diabetes on a stable regimen of diet and exercise, metformin with absent or mild GI symptoms, or SGLT-2 therapy for at least 3 months. Subjects receiving pemvidutide achieved mean weight losses of 4.4%, 6.1% and 7.7% at the 1.2 mg, 1.8 mg, and 2.4 mg doses, respectively, over only 12 weeks of treatment, with the placebo group experiencing a mean weight gain of 0.8% (efficacy estimand using MMRM analysis). Glucose homeostasis was maintained throughout the 12 weeks of treatment, with no significant changes in fasting glucose or HbA1c and no hyperglycemic AEs. No SAEs were observed in patients treated with pemvidutide. Rates of GI AEs were low, and there were no AEs leading to study discontinuation. Phase 1b Type 2 Diabetes Safety Trial—Summary of Efficacy Findings Body weight Placebo (n=14) 1.2 mg (n=14) 1.8 mg (n=13) 2.4 mg (n=13) ∆ Body weight, all subjects %, LSM (SE)1 +0.8 (0.7) -4.4 (1.1)*** -6.1 (1.6)*** -7.7 (1.4)*** 1 MMRM, *** p < 0.001 compared with placebo Phase 1b Type 2 Diabetes Safety Trial—Summary of Safety Findings Placebo (n=14) 1.2 mg (n=14) 1.8 mg (n=13) 2.4 mg (n=13) Glycemic Control Fasting glucose Baseline, mg/dL mean (SD) 140.9 (41.6) 132.6 (25.0) 124.9 (31.0) 128.2 (22.8) Week 24, mg/dL mean (SD) 140.4 (45.4) 132.0 (32.8) 126.2 (15.7) 140.6 (28.7) HbA1c Baseline, % mean (SD) 6.6 (1.3) 6.5 (1.0) 6.6 (0.7) 6.9 (0.7) Week 24, % mean (SD) 7.0 (1.4) 6.5 (0.5) 6.7 (0.8) 7.0 (0.6) Adverse events (AEs) Serious AEs n (%) 1 (7.1%)2 0 (0.0%) 0 (0.0%) 0 (0.0%) Discontinuations due to AE n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Hyperglycemia AEs n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Gastrointestinal AEs Nausea AEs Mild, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 2 (15.4%) Moderate, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (7.7%) Vomiting AEs Mild, n (%) 0 (0.0%) 0 (0.0%) 1 (7.7%) 1 (7.7%) Moderate, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Diarrhea AEs Mild, n (%) 0 (0.0%) 0 (0.0%) 1 (7.7%) 0 (0.0%) Moderate, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) Constipation AEs Mild, n (%) 1 (7.1%) 0 (0.0%) 0 (0.0%) 2 (15.4%) Moderate, n (%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 2 Cervical radiculopathy About Pemvidutide Pemvidutide is a novel, investigational, peptide-based GLP-1/glucagon dual receptor agonist in development for the treatment of obesity and NASH. Activation of the GLP-1 and glucagon receptors is believed to mimic the complementary effects of diet and exercise on weight loss, with GLP-1 suppressing appetite and glucagon increasing energy expenditure. Glucagon is also recognized as having direct effects on hepatic fat metabolism, leading to rapid reductions in levels of liver fat. Pemvidutide incorporates the EuPort™ domain, a proprietary technology that increases its serum half-life for weekly dosing while likely slowing the entry of pemvidutide into the bloodstream, which may improve its tolerability. Conference Call Information Altimmune management will host a conference call and webcast with a slide presentation presented by Dr. Scott Harris, Chief Medical Officer, and Dr. Louis Aronne, Principal Investigator, beginning at 8:30 am E.T. today. Following the conclusion of the call, the webcast will be available for replay on the Investor Relations page of the Company’s website at . The Company has used, and intends to continue to use, the IR portion of its website as a means of disclosing material non-public information and for complying with disclosure obligations under Regulation FD. Conference Call Details: Date: Tuesday, March 21 Time: 8:30 am Eastern Time Webcast: To listen, the conference call will be webcast live on Altimmune’s Investor Relations website at . Dial-in: To participate or dial-in, register here to receive the dial-in numbers and unique PIN to access the call. About Altimmune Altimmune is a clinical-stage biopharmaceutical company focused on the development of novel peptide-based therapeutics for the treatment of obesity and liver diseases. The Company’s lead product candidate, pemvidutide (formerly ALT-801), is a GLP-1/glucagon dual receptor agonist that is being developed for the treatment of obesity and NASH. In addition, Altimmune is developing HepTcell™, an immunotherapeutic designed to achieve a functional cure for chronic hepatitis B. For more information, please visit . Follow @Altimmune, Inc. on LinkedIn Follow @AltimmuneInc on Twitter Forward-Looking Statement Any statements made in this press release relating to future financial or business performance, conditions, plans, prospects, trends, or strategies and other financial and business matters, including without limitation, the timing of key milestones for the Company’s clinical assets, such as the completion of the Company’s 48-week MOMENTUM obesity trial and initiation of the Phase 2 biopsy NASH trial of pemvidutide, and the prospects for regulatory approval, commercializing or selling any product or drug candidates, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In addition, when or if used in this press release, the words “may,” “could,” “should,” “anticipate,” “believe,” “estimate,” “expect,” “intend,” “look forward,” “plan,” “potential,” “predict” and similar expressions and their variants, as they relate to the Company may identify forward-looking statements. The Company cautions that these forward-looking statements are subject to numerous assumptions, risks, and uncertainties, which change over time. Important factors that may cause actual results to differ materially from the results discussed in the forward looking statements or historical experience include risks and uncertainties, including risks relating to: potential impacts such as delays in regulatory review, manufacturing and supply chain interruptions, access to clinical sites, enrollment, adverse effects on healthcare systems and disruption of the global economy; the impact of base line characteristics, such as body weight, and demographics on the success of future trials; the reliability of the results of trials relating to human safety and possible adverse effects resulting from the administration of the Company’s product candidates; the Company’s ability to manufacture clinical trial materials on the timelines anticipated; and the success of future product advancements, including the success of future clinical trials. Further information on the factors and risks that could affect the Company's business, financial conditions and results of operations are contained in the Company’s filings with the U.S. Securities and Exchange Commission (the “SEC”), including under the heading “Risk Factors” in the Company’s annual report on Form 10-K for the most recent fiscal year and the Company’s other filings with the SEC, which are available at . Investor & Media Contacts: Rich Eisenstadt Chief Financial Officer Phone: 240-654-1450 reisenstadt@altimmune.com

Topline data from 12-week Phase 1b trial in subjects with obesity/overweight and non-alcoholic fatty liver disease (NAFLD) expected mid-September 2022GAITHERSBURG, Md., Aug. 11, 2022 (GLOBE NEWSWIRE) -- Altimmune, Inc. (Nasdaq: ALT), a clinical-stage biopharmaceutical company, today announced financial results for the three and six months ended June 30, 2022, and provided a business update. “We continue to advance the development of pemvidutide, our GLP-1/glucagon dual receptor agonist, and look forward to reporting important readouts from our ongoing clinical trials during the coming months,” said Vipin K. Garg, Ph.D., President and Chief Executive Officer of Altimmune. “We expect to announce top line data from our 12-week trial in subjects with obesity/overweight and NAFLD in mid-September 2022, followed by 24-week data from an extension of that trial in Q4 2022. Enrollment in our Phase 2 MOMENTUM obesity trial has been very robust. As of August 10, 167 subjects have been randomized, and approximately 25 additional subjects are being randomized each week. At this rate, we expect to complete the randomization of all 320 subjects in September 2022. We have also made the decision to conduct the interim analysis of this trial when approximately 50%, or 160 study participants, complete 24 weeks of treatment, which we expect will occur in Q1 2023. While we had planned to conduct an interim analysis on approximately 100 subjects at year end 2022, it is our current belief that an interim analysis on 50% of the subjects would be more meaningful.” “We believe that pemvidutide has the potential to deliver weight loss equaling or exceeding 20% after only 48 weeks of treatment. In addition, we believe that pemvidutide will have a highly differentiated product profile compared to other obesity products in development— including, no dose titration, faster weight loss and robust reductions in lipids. If achieved, we believe these features would translate into greater ease of administration, improved adherence to therapy, and greater potential for cardiovascular benefit,” Dr. Garg added. Recent Highlights and Anticipated Milestones: Pemvidutide1 (ALT-801) Topline data from 12-week Phase 1b trial in subjects with obesity/overweight and NAFLD expected mid-September 2022 This trial is being conducted in the U.S., with Dr. Stephen A. Harrison, Director, Pinnacle Research and University of Oxford, serving as Principal Investigator.The trial is fully enrolled and has randomized and dosed a total of 94 subjects, of whom approximately 29% have type 2 diabetes. Treatments included 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo in a 1:1:1:1 ratio administered weekly for 12 weeks.The topline data will include: liver fat assessment by MRI-PDFFweight lossadverse events (AEs leading to discontinuation, rates of gastrointestinal AEs, severe and serious AEs)laboratory parameters, including liver function tests and glucoseserum lipidshemoglobin A1cheart rate and blood pressure Topline data from a 12-week extension to the Phase 1b trial expected in Q4 2022 This extension trial provides 12 weeks of additional treatment to subjects who completed the 12-week Phase 1b trial in subjects with obesity/overweight and NAFLD. This extension allows subjects to receive a total of 24 weeks of treatment.The principal readouts are weight loss and the safety of pemvidutide at 24 weeks of treatment. Enrollment is over 50% complete in 48-week Phase 2 MOMENTUM obesity trial – 24-week interim analysis of 160 subjects expected in Q1 2023 This Phase 2 trial is being conducted at approximately 25 sites in the U.S., with Dr. Lou Aronne, Professor of Clinical Medicine, Weill Cornell Medical College, a leading authority in obesity and obesity clinical trials, serving as the Principal Investigator.The trial is expected to enroll approximately 320 non-diabetic subjects with obesity/overweight with at least one co-morbidity. Subjects are being randomized 1:1:1:1 to 1.2 mg, 1.8 mg, 2.4 mg pemvidutide or placebo administered weekly for 48 weeks in conjunction with diet and exercise.The primary endpoint is the relative (percent) change in body weight at 48 weeks compared to baseline. Additional readouts include metabolic and lipid profiles, cardiovascular measures and glucose homeostasis.As of August 10, 2022, 167 subjects have been randomized and approximately 25 additional subjects are being randomized each week. Based on the current rate of enrollment, Altimmune expects to complete the randomization of all 320 subjects in September 2022.A 24-week interim analysis on approximately 50%, or 160 subjects, is planned in Q1 2023. Enrollment ongoing in Phase 1b trial of diabetic subjects with obesity and overweight This 12-week trial will evaluate the effects of pemvidutide on glucose control in approximately 48 subjects with type 2 diabetes.Completion of enrollment is expected in September 2022, and data readout is expected in Q1 2023. 1proposed INN HepTcell Enrollment continuing in the Phase 2 clinical trial in chronic hepatitis B Endpoints include virological markers of hepatitis B infection and functional cure.Data readout is expected in H2 2023. Financial Results for the Three Months Ended June 30, 2022 Altimmune had cash, cash equivalents and short-term investments totaling $184.8 million at June 30, 2022.Revenue was minimal for the three months ended June 30, 2022 compared to $0.1 million in the same period in 2021. The change in revenue quarter over quarter was primarily due to the discontinuation of development activities for the T-COVID and NasoShield programs.Research and development expenses were $16.0 million for the three months ended June 30, 2022, compared to $13.3 million in the same period in 2021. The expenses for the quarter ended June 30, 2022 included $8.7 million in direct costs related to development activities for pemvidutide and $1.4 million in direct costs related to development activities for HepTcell. In addition, approximately $1.9 million of expense was a non-cash expense associated with the achievement of the Phase 2 development milestone for pemvidutide.General and administrative expenses were $4.4 million for the three months ended June 30, 2022, compared to $3.7 million in the same period in 2021. The change was primarily attributable to increased labor and labor-related expenses, including stock compensation.Net loss for the three months ended June 30, 2022 was $20.1 million, or $0.42 net loss per share, compared to a net loss of $24.8 million, or $0.60 net loss per share, in the same period in 2021. Net loss for the three months ended June 30, 2021 included an $8.1 million impairment loss relating to a write-down of the construction-in-progress associated with the construction of the Lonza facility, which was to manufacture AdCOVID. Conference Call Information: Date:Thursday, August 11Time:8:30 am Eastern TimeWebcast:The conference call will be webcast live on Altimmune’s Investor Relations website at https://ir.altimmune.com/investors.Dial-in:Participants who would like to join the call may register here to receive the dial-in numbers and unique PIN to access the call. Following the conclusion of the call, the webcast will be available for replay on the Investor Relations page of the Company’s website at www.altimmune.com. The Company has used, and intends to continue to use, the IR portion of its website as a means of disclosing material non-public information and for complying with disclosure obligations under Regulation FD. About PemvidutidePemvidutide is a novel, investigational, peptide-based GLP-1/glucagon dual receptor agonist in development for the treatment of obesity and NASH. Activation of the GLP-1 and glucagon receptors is believed to mimic the complementary effects of diet and exercise on weight loss, with GLP-1 suppressing appetite and glucagon increasing energy expenditure. By combining GLP-1 and glucagon activity in a single peptide, pemvidutide has the potential to achieve weight loss equaling or exceeding 20% after only 48 weeks of treatment. Pemvidutide incorporates the EuPortTM domain, a proprietary technology that increases its serum half-life for weekly dosing while slowing the entry of pemvidutide into the bloodstream, which may improve its tolerability. In a 12-week Phase 1 clinical trial, pemvidutide-treated subjects demonstrated striking reductions in body weight, liver fat and serum lipids commonly associated with cardiovascular disease. About HepTcellHepTcell is a novel, investigational, immunotherapeutic comprised of nine synthetic peptides representing conserved hepatitis B (HBV) sequences formulated with IC31®, a TLR9-based adjuvant from Valneva SE. The HBV-directed peptides are designed to drive T cell responses against all HBV genotypes towards a functional cure for chronic HBV in patients of diverse genetic backgrounds. About AltimmuneAltimmune is a clinical-stage biopharmaceutical company focused on the development of novel peptide-based therapeutics for the treatment of obesity and liver diseases. The company’s lead product candidate, pemvidutide, is a GLP-1/glucagon dual receptor agonist that is being developed for the treatment of obesity and NASH. In addition, Altimmune is developing HepTcell™, an immunotherapeutic designed to achieve a functional cure for chronic hepatitis B. For more information, please visit www.altimmune.com. Follow @Altimmune, Inc. on LinkedInFollow @AltimmuneInc on Twitter Forward-Looking Statement Any statements made in this press release relating to future financial or business performance, conditions, plans, prospects, trends, or strategies and other financial and business matters, including without limitation, the timing of key milestones for our clinical assets, the timing of the data readouts of the NAFLD trials, diabetic subject trial, drug-drug interaction trial, and the Phase 2 obesity clinical trial of pemvidutide, the timing of the data readouts for the Phase 2 clinical trial of HepTcell, and the prospects for regulatory approval, use, commercializing or selling any product or drug candidates, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In addition, when or if used in this press release, the words “may,” “could,” “should,” “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “predict” and similar expressions and their variants, as they relate to Altimmune, Inc. (the “Company”) may identify forward-looking statements. The Company cautions that these forward-looking statements are subject to numerous assumptions, risks, and uncertainties, which change over time. Important factors that may cause actual results to differ materially from the results discussed in the forward looking statements or historical experience include risks and uncertainties, including risks relating to: potential impacts from the ongoing conflict in Ukraine and the COVID-19 pandemic, such as delays in regulatory review, manufacturing and supply chain interruptions, access to clinical sites, enrollment, adverse effects on healthcare systems and disruption of the global economy; the reliability of the results of studies relating to human safety and possible adverse effects resulting from the administration of the Company’s product candidates; the Company’s ability to manufacture clinical trial materials on the timelines anticipated; and the success of future product advancements, including the success of future clinical trials. Further information on the factors and risks that could affect the Company's business, financial conditions and results of operations are contained in the Company’s filings with the U.S. Securities and Exchange Commission, including under the heading “Risk Factors” in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2021 and our other filings with the SEC, which are available at www.sec.gov. Investor & Media Contacts: Rich Eisenstadt Chief Financial Officer Phone: 240-654-1450 reisenstadt@altimmune.com ALTIMMUNE, INC.CONSOLIDATED BALANCE SHEETS(In thousands, except share and per share data) June 30, December 31, 2022 2021 (Unaudited) ASSETS Current assets: Cash and cash equivalents $135,858 $190,301 Restricted cash 34 34 Total cash, cash equivalents and restricted cash 135,892 190,335 Short-term investments 48,898 — Accounts receivable 195 429 Income tax and R&D incentive receivables 5,900 5,410 Prepaid expenses and other current assets 4,619 7,952 Total current assets 195,504 204,126 Property and equipment, net 1,236 1,448 Intangible assets, net 12,419 12,419 Other assets 747 872 Total assets $209,906 $218,865 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities: Accounts payable $2,872 $2,034 Contingent consideration — 6,090 Accrued expenses and other current liabilities 10,973 10,152 Total current liabilities 13,845 18,276 Other long-term liabilities 1,526 1,454 Total liabilities 15,371 19,730 Commitments and contingencies (Note 14) Stockholders’ equity: Common stock, $0.0001 par value; 200,000,000 shares authorized; 46,372,105 and 40,993,768 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively 5 4 Additional paid-in capital 532,398 497,342 Accumulated deficit (332,708) (293,171)Accumulated other comprehensive loss, net (5,160) (5,040)Total stockholders’ equity 194,535 199,135 Total liabilities and stockholders’ equity $209,906 $218,865 ALTIMMUNE, INC.CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS(Unaudited)(In thousands, except share and per share data) Three Months Ended Six Months Ended June 30, June 30, 2022 2021 2022 2021 Revenues $8 $137 $40 $975 Operating expenses: Research and development 15,993 13,272 31,097 25,150 General and administrative 4,410 3,659 8,837 7,480 Impairment loss on construction-in-progress — 8,070 — 8,070 Total operating expenses 20,403 25,001 39,934 40,700 Loss from operations (20,395) (24,864) (39,894) (39,725) Other income (expense): Interest expense (65) (22) (127) (34) Interest income 328 33 349 75 Other income (expense), net 25 26 135 (7) Total other income (expense), net 288 37 357 34 Net loss (20,107) (24,827) (39,537) (39,691) Other comprehensive income — unrealized (loss) gain on short-term investments (120) 1 (120) 6 Comprehensive loss $(20,227) $(24,826) $(39,657) $(39,685) Net loss per share, basic and diluted $(0.42) $(0.60) $(0.90) $(0.99) Weighted-average common shares outstanding, basic and diluted 47,502,599 41,356,643 44,150,835 40,142,561